I thought I'd get this thread rolling. This is another of Alex Cavallis amp designs which is available in kit form from Glass Jar audio. It's an interesting design and the basic kit is a very reasonable $110 or so plus shipping etc.

The amp also needs a PSU like the AMB Sigma 22 which is about another $100 or so. There are very few of these in the wild, though a small number of us intrepid explorers are putting a toe into the EHHA waters. Both Don and sachu have heard these and posted favorably on it. Sachu is currently building his and I'm shortly going to start mine

It's all very confusing for a DIY n00b like myself and I'll be asking plenty of questions along the way and posting impressions once completed. I'll be trying to log my progress and mistakes as I go, but first off, here's a pic of the raw kit (glass jar will send a BoM on request) as it arrived.

The kit includes all components needed to populate two boards with parts, tubes, heatsinks and even a pot.

If anyone else is interested in this amp or buys one, please join in the fun.

I love this amp. I mean i really love it. I am smitten by it as Don put it.

I have his amp on my desk as I type this out and mine as well in the final stages of completion. I heard this amplifier first 2 years ago at my first head-fi meet ever in Portland. Needless to say it made a huge impression on me. The orange stacker was there as well, but the EHHA made a bigger impression on me than the stacker.

However over time I have come to realise that the stacker is a very special amp indeed. Each of these two amps have tremendous potential and a lot going for them .

While there has been a lot of excitement around the stacker for obvious reasons, I was dumbfounded to see that there was no info pertaining to this wonderful amplifier here on HF. I was told only 3 were in existence. Such a shame that beautiful elegant designs such as this one get lost in the hullabaloo until someone like me comes along and clears off the dust.

I will get pics up later tonight on the progress of my build. I hope to get the amp up and running later this weekend. Hope everything goes well and the gremlins stay away.

Smeggy, look forward to seeing your build take shape.

I know that wiatrob is planning to make a 3 channel (active ground) version of the EHHA which should be something to look out for.

I had meant to comment on Sachu's long standing LUST for this amp ( he has wanted to take it off my hands on more than one occasion and I nearly relented once, in fact I came close to selling it some time ago but am very glad that all passed ) Getting distracted, this particular amp has always received favourable comments from people at the local meets. "effortless" is one comment I recall from the first meet, I would encourage anyone interested in hybrids to build this as it is not your standard tube VAS followed by SS buffer - read the gory details at Cavalli Audio

BUT
1. it is not really a beginner build
2. Bargain on spending around $350 for a no frills build - 2 X EHHA boards, 1 x S22 power supply ( you can use a more simple supply to keep costs lower but it is worth the S22 ( which is a helluva bargain itself) , a tread or S11 for the tube heaters.

Also consider that you can run the 6H30 in this amp for higher power output and with the necessary mods, it could run small speakers ( altough Alex may be persuaded to open his magic pockets and reveal the most awesome power amp centered around this design )

I don't think I can ever thank dbel84 enough for building the protos of my amps. But the other important person here is Snoopy who inhabits the headwize forum.

I have been buried beyond recognition for the last several weeks and have not been able to attend to all the diy efforts that are afoot.

I must admit that this is a very special amp and like the b22 it will drive small speakers. Although a few small component values would be changed for that.

And yes, there has been an EHHA II done for quite a while. No one has built it yet, but it is not just a headphone amp but capable of making about 100W into 4ohms.

However, it would be insane for me to try to introduce this amp now with everything that's going on. Nonetheless don't be surprised if dBel84 finds the time to build one anyway. Just to prove it can be done.

Thanks to all of you pioneers on this thread. I'm looking forward to what you find.